A barbershop quartet is a musical quartet which performs barbershop music. This form of music dates back to the 1600s, and it evolved, as you might suspect, from casual gatherings of friends in barbershops and other public places. In the United States, barbershop music has long been associated with the black community; barbershop performers often appeared on the vaudeville circuit, at least until the birth of radio made such live performances more rare.
Barbershop music is a type of music which is characterized by having a four part harmony, which is typically led by the second tenor, accompanied by a baritone, a bass, and the first tenor. Barbershop music tends to be very clear in tone, with a standard meter and a very balanced harmonic form; in layman's terms, it just sounds nice, if a bit old-fashioned to some ears. The complex harmonies in barbershop music require the performances of skilled singers, and the four parts lend themselves well to groups of four singers, which is why the barbershop quartet is so common.
Classically, barbershop quartets have decked themselves out as exaggerated dandies, with neat matching suits, straw hats, and bold ties. They tend to dress in coordinating outfits, with the members of the barbershop quartet often donning ludicrous mustaches, in an homage to the history of this musical form. Barbershop quartets are also open to women, and some all-female groups call themselves “beauty shop quartets” as a tongue-in-cheek dig at the traditional barbershop quartet.
One of the most distinctive features of barbershop music is the ringing chord. The ringing chord is a unique vocal effect created when the four voices harmonize perfectly with each other, overlaying in such a way that the illusion of a fifth singer is created. The ringing chord can sound quite ethereal and it is very recognizable; most barbershop groups work hard to attain it, and are rightfully proud when they manage to achieve it.
The barbershop quartet was extremely common in the 19th and early 20th centuries, and some quartets were quite famous. However, with the advent of radio, the demand for live performance started to fade, and many quartets found themselves out of work. In the late 1930s, people began to be concerned that this unique musical form would be lost forever, and they started a barbershop revival to promote the preservation and performance of barbershop music. Members of a barbershop quartet often belong to a revival association so that they can network with fellow musicians with like interests.